A monkey is a type of primate that belongs to the infraorder Simiiformes. They are known for their intelligence, social behavior, and ability to use tools. Monkeys are typically found in tropical forests, savannas, and mountainous regions around the world. They have a wide range of sizes, colors, and physical features, including long tails in many species. Monkeys are divided into two main groups: New World monkeys and Old World monkeys. New World monkeys, found in the Americas, often have prehensile tails, while Old World monkeys, found in Africa and Asia, do not. Both groups are highly social and live in groups called troops, which help them protect against predators and find food.